this vet michelle and her husband cornell professor bob oswald studied 24 cases where animals had problems. >> the changes in breeding, abortions, stillbirths, were more common after drilling than before drilling. >> reporter: which brings us back to george stark. his cabot oil and gas company has racked up a number of violations for allowing natural gas to pollute the local water. >> we got this 2010 letter from the pennsylvania department of environmental protection saying, cabot, "you have leaky pipes. shame on you. >> reporter: what was that about? >> that was at a time in 2010 where there was a question of methane migration. what we discovered is that 70% of the water well here have preexisting methane in them already. >> reporter: today pennsylvania gas companies are required to test homeowners' water before and after fracking. >> live and learn. now we test it everywhere. >> reporter: then there's the disposal problem. what do we do with all the poisonous water that comes back up from the fracked well? >> there are still some states where you can spray that water on lands or where i